Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of figuring out when to plant geranium is to refer to the USDA zone info for San Luis Obispo.

Planting Calendar for Geranium

Frost tolerance for geranium:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

It's not a good idea to plant geranium until after all chance of frost has passed because they do not do well in cold weather.

The earliest that you can plant geranium in San Luis Obispo is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant geranium and expect a good harvest is probably September. You probably don't want to wait any later than that or else your geranium may not have a chance to grow to maturity. You can get started a little bit earlier by starting your geranium indoors.

Last Frost Date

The average date of last frost is February 15 in San Luis Obispo. It might get as low as 25°F during the coldest months of winter.

Always keep in mind that USDA zone info for San Luis Obispo is just an average and the actual date of last frost changes from year to year. Half of the time in San Luis Obispo last frost occurs after February 15 so always be ready to cover your geranium if you have one of those late frosts.

USDA Zone Info for San Luis Obispo

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in San Luis Obispo

You may be interested in your other planting guides for San Luis Obispo.